In recent years, increase of the size of screens and decrease of the size of pixels of a spread display such as an LCD and a PDP have been advanced, and it is very difficult to manufacture non-defective products, and a serious problem occurs in ensuring the yield. Thus, it is a general practice of ensuring the yield by including inspections and repairs in a manufacturing step of the flat display panel to recondition a defective panel as a non-defective one.
In particular, in order to inspect the application state of liquid phosphor applied to a back plate of the PDP, the technology disclosed in, for example, Japanese Unexamined Patent Application Publication No. 2000-131226 is applicable. In this technology, the structure of a measurement surface can be inspected by allowing the light to be incident on the measurement surface of an object to be inspected by light, capturing the reflected light thereby, and measuring the change in intensity of the obtained reflected light.
When carrying out the above inspection using the light, various optical conditions must be optimized according to the structural characteristic of the object in order to increase the accuracy of the inspection. Specific optical conditions include the angle of incidence, the angle of reflection, the wavelength, the intensity, the scattering, and the polarizing direction of the light.
However, in the above conventional technology, any method for optimizing the optical conditions according to the structural characteristic of the object has not been demonstrated, and problems occur in that the shape of the pattern for forming the surface is changed by the change in a manufacturing condition of the object, and the accuracy of the inspection is considerably degraded or the inspection becomes impossible if the structural characteristic is different according to the stage of the manufacturing steps even with the products of the same kind.
The object of the present invention is to provide a method for solving the disadvantages of the above conventional technology, determining the optimum optical condition for the inspection of the surface shape by the structural characteristic of the object to be inspected, reflecting the determined condition in an inspection device to carry out the inspection with high accuracy, improving the yield without degrading the yield rate, and manufacturing a substrate of high quality and high reliability.